Convert browser.version to number for proper comparison
- more clear API to describe tests;
- allow to execute both new and old tests on the same page;
- use sinon fake server for users/whoami and some canvases requests;
- convert the rest test cases for the Echo.Loader module;
- return back several things removed in the previous commits;
- moving other things here and there for better structure.
Simplify _testRenderers check